The recommended latitude for growing hops is from 35 to 55 degrees in
both the northern and southern hemispheres, but hops can often be grown
outside that band. I have broken this post down into labeled sections
in case you prefer to go straight to your own area of the world. After
reading about your area or country, please continue with my "EVERYWHERE"
section at the end of this post for additional information. Sections
are as follows:
U.S.
Canada
Europe
Australia, New Zealand, South Africa
Asia

U.S.:
Contrary to the impression that many people have, cultivation of hops is
not limited to the Pacific Northwest in the U.S. -- Washington, Idaho,
and Oregon -- despite that this is where our commercial hop farming
is concentrated; hops have been grown, with varying degrees of success,
throughout _most_ of the continental U.S. Hops do _prefer_ latitudes
between 35 and 55 -- which is everything in the continental U.S. that
lies north of a line that runs from just north of Los Angelos and goes
east across the Texas panhandle through almost the center of Arkansas
and almost along the southern border of Tennessee and includes most of
North Carolina; however, we do have reports, within my Grow-Hops group,
of successful growers in South Carolina, Georgia, and even as far south
as Austin, Texas, which has a latitude of about 30.25 -- and which is
farther south than ALL of California, Arizona, New Mexico, Mississippi,
Alabama, and Georgia, and all but the very bottom of Texas and Louisiana
and the Florida peninsula. We also have a successful grower in Hawaii.
So, hops should be _capable_ of growing in nearly all of the continental
U.S. with the proper care, if anyone is interested in giving it a try.

Canada:
The recommended 35-to-55 latitude band covers probably 95% of Canada's
populated area, including everything south of a line that runs east-west
through _about_ the middle of British Columbia, Alberta, Saskatchewan,
Manitoba, and includes most of Ontario and Quebec. Unlike the additional
'marginal' band in the south (see U.S., above), I will be surprised if
hops will grow _much_ farther north than latitude 55 degrees because of
late frost days and cold temperatures which can't be remedied as easily
as short daylight. But we do have a member in Sweden who is going to
try, and I believe we also have members in Scotland (most is N of '55').

Europe:
The recommended latitude band of 35-to-55 includes almost all of Europe,
including all of Spain, Italy and Sicily (although they are not known
for growing hops), and excludes only part of Northern Ireland, and most
of Scotland, Denmark, and countries around the Baltic Sea and north of
Poland. However, we do have a member in Sweden who is going to give it
a try.

Australia, New Zealand, South Africa:
In the southern hemisphere, the same recommended latitude band of 35-55
degrees applies. In Australia, only the southern portion falls within
it -- south of a line from about Adelaide to Canberra -- but Perth and
Sydney are well within that addition area above 30 degrees in which hops
can be grown in the U.S., so perhaps it works there, too. All of New
Zealand is in the preferred band. For all practical purposes, all of
South Africa lies below the preferred band, with most of it even lower
than the marginal 30-35 degrees, which is why electric lights are
usually used to supplement daylight, as will be explained below.

Asia:
I'll mention part of Asia, too, since I've read a _few_ posts in brewing
forums from homebrewers in Japan and South Korea -- almost all of those
two countries lie within the preferred band, with the rest being inside
the marginal band, so hops should grow there, too. China, of course, is
a major grower of hops with plenty of area in the preferred band.

EVERYWHERE:
The problem with latitudes which are much below 35 -- actually probably
below '30', since they apparently will often still grow okay from 30-35
-- is that the length of daylight is too short; yes, despite the hotter
climate, 'daylight' is actually shorter in places closer to the equator
because during summer in the northern hemisphere, it is lit 24 hours/day
at the North Pole and dark 24 hours/day at the South Pole. But there is
still a reasonable solution even below latitude 30 for any diehards out
there; in South Africa, for instance, which also has daylight which is
too short, growers use electric lights to trick the hops into thinking
that the daylight is longer, and the number of lights and their wattage
is not as high as one might think would be necessary. In other words,
for just a couple of bucks worth of electricity, you can still grow many
times that amount worth of hops. However, an added problem in warm
climates is 'vernalization' already discussed in another thread. More
detailed info is available about all of this in our discussion forum.

Our 'Grow-Hops' Yahoo Group is less than nine months old but already has
1,012 members as of this post, and has been growing very rapidly in the
past couple of months due to rising interest among homebrewers trying to
find ways to ensure a supply of the hops they want at reasonable prices.
If interested, please visit http://groups.yahoo.com/group/Grow-Hops